The present invention concerns the use of a distributed priority list in order to implement a distributed fair arbitration scheme for providing agents with access to a data communication bus. An agent is a module on a bus which can master transactions.
When many agents simultaneously seek access to a bus, some type of arbitration scheme needs to be used to determine which agent may use the bus for its data transaction. In the prior art a number of schemes have been used. For example, in parallel contention schemes each agent is assigned an arbitration number which determines its access priority to the bus. In Round Robin Schemes there is a dynamic assignment of arbitration numbers and thus access priority to the bus is dynamic. In First-Come First-Served schemes there is an attempt to award an agent access to the bus in the order that the agents request access. In all these schemes there is an attempt to provide agents fair access to the bus with minimal overhead or implementation cost.